Method for compensating aberration of variable focus liquid lens

Abstract

A method for compensating an aberration of a variable focus liquid lens is configured to compensate the aberration associated with a first lens surface and a second lens surface of the liquid lens. The first lens surface is of a first radius of curvature. The second lens surface is of a second radius of curvature.

What is claimed is: 
     
       1. A method for compensating an aberration of a variable focus liquid lens, wherein, in step S 1 , the liquid lens has a selected diameter, a lens thickness, and a refractive index of a liquid filled into the liquid lens, the method being applied to compensate the aberration produced by a first lens surface and a second lens surface of the liquid lens according to the aforesaid requirements, the method comprising:
 S 2 : selecting one of the lens magnifying powers which is produced according to the diameter, the lens thickness, and the refractive index, and obtaining a plurality of combinations of radii of curvature corresponding to the lens magnifying power selected, wherein each combination of radii of curvature corresponds to the first lens surface and the second lens surface; 
 S 3 : calculating spherical aberration corresponding to each combination of radii of curvature according to the obtained combinations of radii of curvature; 
 S 4 : selecting a least spherical aberration from the spherical aberrations to obtain the combination of radii of curvature corresponding to the least spherical aberration, so as to generate a curvature radius ratio of the first lens surface and the second lens surface according to the combination of radii of curvature corresponding to the least spherical aberration; 
 S 5 : selecting another one of the lens power-magnifying, and, obtaining a plurality of combinations of radii of curvature corresponding to the lens magnifying power selected, repeating the steps S 2  through S 5  until the curvature radius ratios corresponding to all the lens magnifying powers of the variable focus liquid lens respectively are obtained, and obtaining an average curvature radius ratio of the variable focus liquid lens based on the curvature radius ratios; 
 S 6 : calculating a film deformation ratio or a film stiffness ratio according to the radius of curvature corresponding to the first lens surface and the second lens surface of the selected average curvature radius ratio, wherein the film deformation ratio or the film stiffness ratio is a thickness ratio; and 
 S 7 : selecting a first film and a second film corresponding to the thickness ratio and using the selected first film and second film as the first lens surface and the second lens surface for compensating the aberration of the liquid lens, respectively. 
 
     
     
       2. The method as recited in  claim 1 , wherein the curvature radius ratio is represented by P min =r 1 /r 2  further wherein P min  is the curvature radius ratio, r 1  and r 2  are the first radius of curvature and the second radius of curvature of the first lens surface and the second lens surface according to the selected combinations of radii of curvature, respectively. 
     
     
       3. The method as recited in  claim 1 , wherein, in step S 5 , the average curvature radius ratio of the curvature radius ratios is calculated by a weighted average method. 
     
     
       4. The method as recited in  claim 3 , wherein the weighted average is weighted in a direct proportion to the corresponding curvature radius ratio according to the power-magnifying from a high magnifying power to a low magnifying power. 
     
     
       5. The method as recited in  claim 1 , wherein the film deformation ratio is represented by T=Δl r1 /Δl r2  further wherein T is the film deformation ratio, Δl r1  and Δl r2  are a first expanded deformation and a second expanded deformation which occur at radii of curvature corresponding to the average curvature radius ratio, respectively. 
     
     
       6. The method as recited in  claim 1 , wherein the film stiffness ratio is represented by T=K 2 /K 1  further wherein T is the film stiffness ratio, K 1  and K 2  are the stiffness coefficient of the first lens surface and the stiffness coefficient of the second lens surface at the radii of curvature corresponding to the average curvature radius ratio, respectively. 
     
     
       7. The method as recited in  claim 5 , wherein the film deformation ratio and the stiffness ratio are used for determining the thickness ratio of the first film to the second film. 
     
     
       8. The method as recited in  claim 6 , wherein the film deformation ratio and the stiffness ratio are used for determining the thickness ratio of the first film to the second film. 
     
     
       9. The method as recited in  claim 7 , wherein the first film or the second film with a larger thickness is selected to align towards an observing object. 
     
     
       10. The method as recited in  claim 1 , wherein the first film or the second film produces an expanded deformation by a liquid filled into the liquid lens and expanded convexly outward, and the first radius of curvature or the second radius of curvature of the first film or the second film is represented by Δl i =2·(r i ·sin −1 (r d /r i )−r d ), futher wherein Δl i  is the expanded deformation, r i  is the first radius of curvature or the second radius of curvature corresponding to the expanded deformation, r d  is the diameter, and i is equal to 1 or 2.